TY - JOUR
A1 - Biesen, L.
A1 - May, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - Communication of Bichromophore Emission upon Aggregation – Aroyl-S,N-ketene Acetals as Multifunctional Sensor Merocyanines
N2 - Aroyl-S,N-ketene acetal-based bichromophores can be readily synthesized in a consecutive three-component synthesis in good to excellent yields by condensation of aroyl chlorides and an N-(p-bromobenzyl) 2-methyl benzothiazolium salt followed by a Suzuki coupling, yielding a library of 31 bichromophoric fluorophores with substitution patterntunable emission properties. Varying both chromophores enables different communication pathways between the chromophores, exploiting aggregation-induced emission (AIE) and energy transfer (ET) properties, and thus, furnishing aggregation-based fluorescence switches. Possible applications range from fluorometric analysis of alcoholic beverages to pH sensors.
KW - Dye
KW - Fluorescence
KW - Aggregation induced emission
KW - Signal enhancement
KW - Energy transfer
KW - Switch
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531123
DO - https://doi.org/10.1002/chem.202102052
VL - 27
IS - 53
SP - 13426
EP - 13434
PB - Wiley-VCH
AN - OPUS4-53112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, F.
A1 - Fiedler, S.
A1 - Bardan, A.
A1 - Güttler, Arne
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Influence of Measurement Geometry and Blank on Absolute Measurements of Photoluminescence Quantum Yields of Scattering Luminescent Films
N2 - For a series of 500 μm-thick polyurethane films containing different concentrations of luminescent and scattering YAG:Ce microparticles, we systematically explored and quantified pitfalls of absolute measurements of photoluminescence quantum yields (Φf) for often employed integrating sphere (IS) geometries, where the sample is placed either on a sample holder at the bottom of the IS surface or mounted in the IS center. Thereby, the influence of detection and illumination geometry and sample position was examined using blanks with various scattering properties for measuring the number of photons absorbed by the sample. Our results reveal that (i) setup configurations where the scattering sample is mounted in the IS center and (ii) transparent blanks can introduce systematic errors in absolute Φf measurements.
For strongly scattering, luminescent samples, this can result in either an under- or overestimation of the absorbed photon flux and hence an under- or overestimation of Φf. The size of these uncertainties depends on the scattering properties of the sample and instrument parameters, such as sample position, IS size, wavelength-dependent reflectivity of the IS surface coating, and port configuration. For accurate and reliable absolute Φf measurements, we recommend (i) a blank with scattering properties closely matching those of the sample to realize similar distributions of the diffusely scattered excitation photons within the IS, and (ii) a sufficiently high sample absorption at the excitation wavelength. For IS setups with center-mounted samples, measurement geometries should be utilized that prevent the loss of excitation photons by reflections from the sample out of the IS.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Quantum yield
KW - Characterization
KW - Silica
KW - Scattering
KW - Uncertainty
KW - Film
KW - Pphosphor
KW - YAG:Ce
KW - LED
KW - Converter material
KW - Solid material
KW - Polymer
KW - Composite material
KW - Advanced material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638304
DO - https://doi.org/10.1021/acs.analchem.4c06726
SN - 1520-6882
SP - 1
EP - 8
PB - ACS Publications
AN - OPUS4-63830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, R.
A1 - Teich, W.
A1 - Frenzel, Florian
A1 - Hoffmann, Katrin
A1 - Radke, J.
A1 - Rösler, J.
A1 - Faust, K.
A1 - Blank, A.
A1 - Brandenburg, S.
A1 - Misch, M.
A1 - Vajkoczy, P.
A1 - Onken, J. S.
A1 - Resch-Genger, Ute
T1 - Optical characterization of sodium fluorescein in vitro and ex vivo
N2 - Objective: The utilization of fluorescein-guided biopsies and resection has been recently discussed as a suitable strategy to improve and expedite operative techniques for the resection of central nervous system (CNS) tumors. However, little is known about the optical properties of sodium fluorescein (NaFl) in human tumor tissue and their potential impact on ex vivo analyses involving fluorescence-based methods.
Methods: Tumor tissue was obtained from a study cohort of an observational study on the utilization of fluorescein-guided biopsy and resection (n=5). The optical properties of fluorescein-stained tissue were compared to the optical features of the dye in vitro and in control samples consisting of tumor tissue of high-grade glioma patients (n=3) without intravenous (i.v.) application of NaFl. The dye-exposed tumor tissues were used for optical measurements to confirm the detectability of NaFl emission ex vivo. The tissue samples were fixed in 4%PFA, immersed in 30% sucrose, embedded in Tissue-Tek OCT compound, and cut to 10 mm cryosections. Spatially resolved emission spectra from tumor samples were recorded on representative slides with a Confocal Laser Scanning Microscope FV1000 (Olympus GmbH, Hamburg, Germany) upon excitation with lexc = 488 nm.
Results: Optical measurements of fluorescein in 0.9% sodium chloride (NaCl) under in vitro conditions showed an absorption maximum of lmax abs = 479 nm as detected with spectrophotometer Specord 200 and an emission peak at lmax em = 538 nm recorded with the emCCD detection system of a custom-made microscope-based single particle setup using a 500 nm long-pass filter. Further measurements revealed pH- and concentration-dependent emission spectra of NaFl. Under ex vivo conditions, confocal laser scanning microscopy of fluorescein tumor samples revealed a slight bathochromic shift and a broadening of the emission band.
Conclusion: Tumor uptake of NaFl leads to changes in the optical properties – a bathochromic shift and broadening of the emission band – possibly caused by the dye’s high pH sensitivity and concentration-dependent reabsorption acting as an innerfilter of the dye’s emission, particularly in the short wavelength region of the Emission spectrum where absorption and fluorescence overlap. Understanding the ex vivo optical properties of fluorescein is crucial for testing and validating its further applicability as an optical probe for intravital microscopy, immunofluorescence localization studies, and flow cytometry analysis.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Fluorescein
KW - PH
KW - Imaging
KW - Tissue
KW - Cancer
KW - Medical diagnostics
KW - Tumor
KW - In vivo
KW - Ex vivo
KW - Quantum yield
KW - Dye
KW - Quality assurance
KW - Microscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527843
DO - https://doi.org/10.3389/fonc.2021.654300
SN - 2234-943X
VL - 11
SP - 1
EP - 8
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-52784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nelson, G.
A1 - Boehm, U.
A1 - Bagley, S.
A1 - Bajcsy, P.
A1 - Bischof, J.
A1 - Brown, C. M.
A1 - Dauphin, A.
A1 - Dobbie, I. M.
A1 - Eriksson, J. E.
A1 - Faklaris, O.
A1 - Fernandez-Rodriguez, J.
A1 - Ferrand, A.
A1 - Gelman, L,
A1 - Gheisari, A.
A1 - Hartmann, H.
A1 - Kukat, C.
A1 - Laude, A.
A1 - Mitkovski, M.
A1 - Munck, S.
A1 - North, A. J.
A1 - Rasse, T.
A1 - Resch-Genger, Ute
A1 - Schuetz, L. C.
A1 - Seitz, A.
A1 - Strambio-De-Castillia, C.
A1 - Swedlow, J. R.
A1 - Alexopoulos, I.
A1 - Aumayr, K.
A1 - Avilov, S.
A1 - Bakker, G.-J.
A1 - Bammann, R. R.
A1 - Bassi, A.
A1 - Beckert, H.
A1 - Beer, S.
A1 - Belyaev, Y.
A1 - Bierwagen, J.
A1 - Birngruber, K. A.
A1 - Bosch, M.
A1 - Breitlow, J.
A1 - Cameron, L. A.
A1 - Chalfoun, J.
A1 - Chambers, J. J.
A1 - Chen, C.-L.
A1 - Conde-Sousa, E.
A1 - Corbett, A. D.
A1 - Cordelieres, F. P.
A1 - Del Nery, E.
A1 - Dietzel, R.
A1 - Eismann, F.
A1 - Fazeli, E.
A1 - Felscher, A.
A1 - Fried, H.
A1 - Gaudreault, N.
A1 - Goh, W. I.
A1 - Guilbert, T.
A1 - Hadleigh, R.
A1 - Hemmerich, P.
A1 - Holst, G. A.
A1 - Itano, M. S.
A1 - Jaffe, C. B.
A1 - Jambor, H. K.
A1 - Jarvis, S. C.
A1 - Keppler, A.
A1 - Kirchenbuechler, D.
A1 - Kirchner, M.
A1 - Kobayashi, N.
A1 - Krens, G.
A1 - Kunis, S.
A1 - Lacoste, J.
A1 - Marcello, M.
A1 - Martins, G. G.
A1 - Metcalf, D. J.
A1 - Mitchell, C. A.
A1 - Moore, J.
A1 - Mueller, T.
A1 - Nelson, M. S.
A1 - Ogg, S.
A1 - Onami, S.
A1 - Palmer, A. L.
A1 - Paul-Gilloteaux, P.
A1 - Pimentel, J. A.
A1 - Plantard, L.
A1 - Podder, S.
A1 - Rexhepaj, E.
A1 - Royon, A.
A1 - Saari, M. A.
A1 - Schapman, D.
A1 - Schoonderwoert, V.
A1 - Schroth-Diez, B.
A1 - Schwartz, S.
A1 - Shaw, M.
A1 - Spitaler, M.
A1 - Stoeckl, M. T.
A1 - Sudar, D.
A1 - Teillon, J.
A1 - Terjung, S.
A1 - Thuenauer, R.
A1 - Wilms, C. D.
A1 - Wright, G. D.
A1 - Nitschke, R.
T1 - QUAREP-LiMi: A community-driven initiative to establish guidelines for quality assessment and reproducibility for instruments and images in light microscopy
N2 - A modern day light microscope has evolved from a tool devoted to making primarily empirical observations to what is now a sophisticated, quantitative device that is an integral part of both physical and life science research. Nowadays, microscopes are found in nearly every experimental laboratory. However, despite their prevalent use in capturing and quantifying scientific phenomena, neither a thorough understanding of the principles underlying quantitative imaging techniques nor appropriate knowledge of how to calibrate, operate and maintain microscopes can be taken for granted. This is clearly demonstrated by the well-documented and widespread difficulties that are routinely encountered in evaluating acquired data and reproducing scientific experiments. Indeed, studies have shown that more than 70% of researchers have tried and failed to repeat another scientist’s experiments, while more than half have even failed to reproduce their own experiments1. One factor behind the reproducibility crisis of experiments published in scientific journals is the frequent underreporting of imaging methods caused by a lack of awareness and/or a lack of knowledge of the applied technique2,3. Whereas quality control procedures for some methods used in biomedical research, such as genomics (e.g., DNA sequencing, RNA-seq) or cytometry, have been introduced (e.g. ENCODE4), this issue has not been tackled for optical microscopy instrumentation and images. Although many calibration standards and protocols have been published, there is a lack of awareness and agreement on common Standards and guidelines for quality assessment and reproducibility5.
In April 2020, the QUality Assessment and REProducibility for instruments and images in Light Microscopy (QUAREP-LiMi) initiative6 was formed. This initiative comprises imaging scientists from academia and industry who share a common interest in achieving a better understanding of the performance and limitations of microscopes and improved quality control (QC) in light microscopy. The ultimate goal of the QUAREP-LiMi initiative is to establish a set of common QC standards, guidelines, metadata models7,8, and tools9,10, including detailed protocols, with the ultimate aim of improving reproducible advances in scientific research.
This White Paper 1) summarizes the major obstacles identified in the field that motivated the launch of the QUAREP-LiMi initiative; 2) identifies the urgent need to address these obstacles in a grassroots manner, through a community of Stakeholders including, researchers, imaging scientists11, bioimage analysts, bioimage informatics developers, corporate partners, Funding agencies, standards organizations, scientific publishers, and observers of such; 3) outlines the current actions of the QUAREPLiMi initiative, and 4) proposes future steps that can be taken to improve the dissemination and acceptance of the proposed guidelines to manage QC.
To summarize, the principal goal of the QUAREP-LiMi initiative is to improve the overall quality and reproducibility of light microscope image data by introducing broadly accepted standard practices and accurately captured image data metrics.
KW - Fluorescence
KW - Microscopy
KW - Quality assurance
KW - Comparability
KW - Imaging
KW - Standards
KW - Reference materials
KW - Reliability
KW - Data
KW - Reference data
KW - Biology
KW - Medicine
KW - Life science
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530629
DO - https://doi.org/10.1111/jmi.13041
SN - 1365-2818
VL - 284
IS - 1
SP - 56
EP - 73
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-53062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keller, Julia
A1 - Moldenhauer, Daniel
A1 - Byrne, L.
A1 - Haase, H.
A1 - Resch-Genger, Ute
A1 - Koch, Matthias
T1 - Complexes of the mycotoxins citrinin and ochratoxin A with aluminum ions and their spectroscopic properties
N2 - The sensitive detection of the mycotoxin citrinin (CIT) utilizing ist fluorescence requires approaches to enhance the emission. In this respect, we studied the complexation of CIT and ochratoxin A (OTA) with Al3+ in methanol using absorption and fluorescence spectroscopy. In this context, an isocratic high performance liquid chromatography (HPLC) method using a polymer column and a fluorescence detector was also developed that enables the separation of the metal ion complexes from the free ligands and non-complexed Al3+. CIT and OTA showed distinct changes in their absorption and fluorescence properties upon Al3+-coordination, and the fluorescence of CIT was considerably enhanced. Analysis of the photometrically assessed titration of CIT and OTA with Al3+ using the Job plot method revealed 1:2 and 1:1 stoichiometries for the Al3+ complexes of CIT (Al:CIT) and OTA (Al:OTA), respectively. In the case of CIT, only one -diketone moiety participates in Al3+ coordination. These findings can be elegantly exploited for signal amplification and provide the base to reduce the limit of detection for CIT quantification by about an order of magnitude, as revealed by HPLC measurements using a fluorescence detector.
KW - Complexation
KW - Aluminum
KW - Fluorescence
KW - Job plot
KW - HPLC-DAD/FLD
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470502
DO - https://doi.org/10.3390/toxins10120538
SN - 2072-6651
VL - 10
IS - 12
SP - 538, 1
EP - 8
PB - MDPI
CY - Basel
AN - OPUS4-47050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kage, Daniel
A1 - Hoffmann, Katrin
A1 - Borcherding, H.
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Lifetime encoding in flow cytometry for bead‑based sensing of biomolecular interaction
N2 - To demonstrate the potential of time-resolved flow cytometry (FCM) for bioanalysis, clinical diagnostics, and optically encoded bead-based assays, we performed a proof-of-principle study to detect biomolecular interactions utilizing fluorescence lifetime (LT)-encoded micron-sized polymer beads bearing target-specific bioligands and a recently developed prototype lifetime flow cytometer (LT-FCM setup). This instrument is equipped with a single excitation light source and different fluorescence detectors, one operated in the photon-counting mode for time-resolved measurements of fluorescence decays and three detectors for conventional intensity measurements in different spectral windows. First, discrimination of bead-bound biomolecules was demonstrated in the time domain exemplarily for two targets, Streptavidin (SAv) and the tumor marker human chorionic gonadotropin (HCG). In a second step, the determination of biomolecule concentration levels was addressed representatively for the inflammation-related biomarker tumor necrosis factor (TNF-α) utilizing fluorescence intensity measurements in a second channel of the LT-FCM instrument. Our results underline the applicability of LT-FCM in the time domain for measurements of biomolecular interactions in suspension assays. In the future, the combination of spectral and LT encoding and multiplexing and the expansion of the time scale from the lower nanosecond range to the longer nanosecond and the microsecond region is expected to provide many distinguishable codes. This enables an increasing degree of multiplexing which could be attractive for high throughput screening applications.
KW - Fluorescence
KW - Sensor
KW - Assay
KW - Protein
KW - Multiplexing
KW - Flow cytometry
KW - Barcoding
KW - Lifetime
KW - Dye
KW - Bead
KW - Bead-based assay
KW - Method
KW - Quantification
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516007
DO - https://doi.org/10.1038/s41598-020-76150-x
VL - 10
IS - 1
SP - 19477
PB - Nature
AN - OPUS4-51600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, Katrin
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
T1 - Fluorescence calibration standards made from broadband emitters encapsulated in polymer beads for fluorescence microscopy and flow cytometry
N2 - We present here the design and characterization of a set of spectral calibration beads. These calibration beads are intended for the determination and regular control of the spectral characteristics of fluorescence microscopes and other fluorescence measuring devices for the readout of bead-based assays. This set consists of micrometer-sized polymer beads loaded with dyes from the liquid Calibration Kit Spectral Fluorescence Standards developed and certified by BAM for the wavelength-dependent Determination of the spectral responsivity of fluorescencemeasuring devices like spectrofluorometers. To cover the wavelength Region from 400 to 800 nm, two new near-infrared emissive dyes were included, which were spectroscopically characterized in solution and encapsulated in the beads. The resulting set of beads presents the first step towards a new platform of spectral calibration beads for the determination of the spectral characteristics of fluorescence instruments like fluorescence microscopes, FCM setups, and microtiter plate readers, thereby meeting the increasing demand for reliable and comparable fluorescence data especially in strongly regulated areas, e.g., medical diagnostics. This will eventually provide the basis for standardized calibration procedures for imaging systems as an alternative to microchannel slides containing dye solutions previously reported by us.
KW - Fluorescence standard
KW - Fluorescence
KW - Dye
KW - Microscopy
KW - Bead
KW - Particle
KW - NIR
KW - calibration
KW - Quality assurance
KW - Traceability
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508117
DO - https://doi.org/10.1007/s00216-020-02664-y
SN - 1618-2642
VL - 412
IS - 24
SP - 6499
EP - 6507
PB - Springer
AN - OPUS4-50811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srivastava, Priyanka
A1 - Fürstenwerth, Paul Christian
A1 - Witte, J. F.
A1 - Resch-Genger, Ute
T1 - Synthesis and spectroscopic characterization of a fluorescent phenanthrene-rhodamine dyad for ratiometric measurements of acid pH values
N2 - We present the rational design, synthesis and spectroscopic characterization of a novel dual excitation, three color emitting, pH-responsive fluorescent probe consisting of two phenanthrene and one rhodamine B units linked by click chemistry. The rhodamine moiety, excitable at λEx = 315 nm and at λEx = 560 nm in its ring-opened form, provides the pH-responsive fluorophore, while the pH-insensitive phenanthrene, excited at λEx = 315 nm, serves as inert internal reference, The presence of two phenanthrene moieties enables a blue monomer and a blueish green excimer emission at 351 nm and 500 nm, respectively. Opening of the rhodamine B spirolactam ring at an acidic pH below 5.0 (pKa = 2.59 ± 0.04) switches on its emission at 580 nm. Simultaneously, the phenanthrene excimer emission decreases caused by a change in orientation of the phenanthrene units, while the monomer emission is barely affected. This sensor design enables ratiometric measurements in the low acidic pH range utilizing the intensity ratios of the rhodamine B and phenanthrene excimer emission at 580 nm and 500 nm. Alternatively, also the intensity ratios of the rhodamine B and the phenanthrene monomer emission could be exploited or the sum of the phenanthrene monomer and excimer fluorescence. To the best of our knowledge, this is the first report of ratiometric sensing utilizing such a versatile type of tricolor emissive dyad probe bearing phenanthrene moieties and showing phenanthrene monomer and excimer emission.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Rhodamine
KW - Synthesis
KW - Photophysics
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Mechanism
KW - Chemodosimeter
KW - Phenanthrene
KW - Ratiometric
KW - Dyad
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530554
DO - https://doi.org/10.1039/d1nj01573g
SN - 1144-0546
VL - 45
IS - 31
SP - 13755
EP - 13762
PB - Royal Society of Chemistry
AN - OPUS4-53055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wasternack, J.
A1 - Schröder, H. V.
A1 - Witte, J. F.
A1 - Ilisson, M.
A1 - Hupatz, H.
A1 - Hille, J. F.
A1 - Gaedke, M.
A1 - Valkonen, A. M.
A1 - Sobottka, S.
A1 - Krappe, A.
A1 - Schubert, M.
A1 - Paulus, B.
A1 - Rissanen, K.
A1 - Sarkar, B.
A1 - Eigler, S.
A1 - Resch-Genger, Ute
A1 - Schalley, C. A.
T1 - Switchable protection and exposure of a sensitive squaraine dye within a redox active rotaxane
N2 - In nature,molecular environments in proteins can sterically protect and stabilize reactive species such as organic radicals through non-covalent interactions.Here, wereport a near-infrared fluorescent rotaxane in which the stabilization of a chemically labile squaraine fluorophore by the coordination of a tetralactam macrocycle can be controlled chemically and electrochemically. The rotaxane can be switched between two co-conformations inwhich thewheel either stabilizes or exposes the fluorophore. Coordination by the wheel affects the squaraine’s stability across four redox states and renders the radical anion significantly more stable—by a factor of 6.7—than without protection by a mechanically bonded wheel. Furthermore, the fluorescence properties can be tuned by the redox reactions in a stepwise manner. Mechanically interlockedmolecules provide an excellent scaffold to stabilize and selectively expose reactive species in a co-conformational switching process controlled by external stimuli.
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Quantum yield
KW - Spectroscopy
KW - Photophysics
KW - Synthesis
KW - Squaraine
KW - Switch
KW - Redox-active
KW - Rotaxane
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614959
DO - https://doi.org/10.1038/s42004-024-01312-1
VL - 7
SP - 1
EP - 11
AN - OPUS4-61495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Hecht, Mandy
A1 - Witthuhn, Heike
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Mix‐&‐read determination of Mercury(II) at trace levels with hybrid mesoporous silica materials incorporating fluorescent probes by a simple mix‐&‐load technique
N2 - The synthesis, characterization, and application of mesoporous materials containing boron–dipyrromethene (BODIPY) moieties that allow the sensitive and selective detection of HgII in aqueous environments by fluorescence enhancement is reported. For this purpose, BODIPY dye I containing a thia‐aza crown ether receptor as the fluorescent probe for the detection of HgII in aqueous environments is encapsulated into mesoporous materials to avoid self‐quenching or aggregation in water. Determination of HgII is accomplished within a few seconds with high selectivity and sensitivity, reaching a limit of detection of 12 ppt. The determination of trace amounts of HgII in natural waters and in fish extracts is demonstrated by using our sensing material. The incorporation of the material into several μ‐PAD strips yields a portable, cheap, quick, and easy‐to‐handle tool for trace HgII analysis in water.
KW - Dyes/pigments
KW - Test strips
KW - Mesoporous materials
KW - Mercury
KW - Fluorescence
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-460138
DO - https://doi.org/10.1002/open.201800277
SN - 2191-1363
VL - 7
IS - 12
SP - 957
EP - 968
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-46013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Alnajjar, M. A.
A1 - Bartelmeß, Jürgen
A1 - Hein, R.
A1 - Ashokkumar, Pichandi
A1 - Nilam, M.
A1 - Nau, W. M.
A1 - Rurack, Knut
A1 - Hennig, A.
T1 - Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril
N2 - We introduce herein boron-dipyrromethene (BODIPY) dyes as a new class of fluorophores for the design of reporter dyes for supramolecular host–guest complex formation with cucurbit[7]uril (CB7). The BODIPYs contain a protonatable aniline nitrogen in the meso-position of the BODIPY chromophore, which was functionalized with known binding motifs for CB7. The unprotonated dyes show low fluorescence due to photoinduced electron transfer (PET), whereas the protonated dyes are highly fluorescent. Encapsulation of the binding motif inside CB7 positions the aniline nitrogen at the carbonyl rim of CB7, which affects the pKa value, and leads to a host-induced protonation and thus to a fluorescence increase. The possibility to tune binding affinities and pKa values
is demonstrated and it is shown that, in combination with the beneficial photophysical properties of BODIPYs, several new applications of host–dye reporter pairs can be implemented. This includes indicator displacement assays with favourable absorption and
emission wavelengths in the visible spectral region, fluorescence correlation spectroscopy, and noncovalent surface functionalization
with fluorophores.
KW - BODIPY
KW - Cucurbituril
KW - Fluorescence
KW - PH
KW - Photoinduced Electron Transfer
KW - Supramolecular Chemistry
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456361
UR - https://www.beilstein-journals.org/bjoc/content/pdf/1860-5397-14-171.pdf
DO - https://doi.org/10.3762/bjoc.14.171
SN - 1860-5397
VL - 14
SP - 1961
EP - 1971
PB - Beilstein-Institut
CY - Frankfurt a. M.
AN - OPUS4-45636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Hecht, Mandy
A1 - Witthuhn, Heike
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Cover profile for the article "Mix‐&‐read determination of Mercury(II) at trace levels with hybrid mesoporous silica materials incorporating fluorescent probes by a simple mix‐&‐load technique"
N2 - Invited for this month’s cover picture is the group of Dr. Knut Rurack at the Department of Analytical Chemistry; Reference Materials at the Bundesanstalt fuer Materialforschung und -pruefung (BAM) in Berlin (Germany). The cover picture shows how differences in color and fluorescence on a test strip can be easily read out with a mobile device. Two reference spots Frame the sensitive spot that indicates the presence of trace amounts of HgII below the threshold in a natural water sample. This dipstick contains a hybrid material that combines boron-dipyrromethene (BODIPY) probes sterically loaded into specifically tailored mesoporous silica particles, allowing for ultrasensitive HgII detection through enhanced fluorescence in a few seconds. The applicability in real water samples and fish extracts are also studied.
KW - Mercury
KW - Fluorescence
KW - Dip-stick assay
KW - Group profile
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471267
DO - https://doi.org/10.1002/open.201800231
SN - 2191-1363
VL - 7
IS - 12
SP - 932
EP - 933
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-47126
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hudson, A.D.
A1 - Jamieson, O.
A1 - Crapnell, R.D.
A1 - Rurack, Knut
A1 - Soares, T.C.C.
A1 - Mecozzi, F.
A1 - Laude, A.
A1 - Gruber, J.
A1 - Novakovic, K.
A1 - Peeters, M.
T1 - Dual detection of nafcillin using a molecularly imprinted polymer-based platform coupled to thermal and fluorescence read-out
N2 - Reported here is the production of molecularly imprinted polymer (MIP) films, integrating a fluorescent moiety that serves as both an element for template interaction and signalling, for the thermal and optical detection of the beta-lactam antibiotic nafcillin. Fluorescein methacrylate (FluMa) was synthesized and introduced during the molecular imprinting process as the sole monomer and in a 1 : 1 mixture with methacrylic acid (MAA), allowing to draw first conclusions on the MIP formation potential of such a rather large and rigid monomer. At first, MIP microparticles containing FluMa were prepared by free radical polymerisation. Optical batch rebinding experiments revealed that FluMa can act as a functional monomer for selective detection of nafcillin; however, the addition of MAA as co-monomer significantly improved performance. Subsequently, thin MIP films containing FluMa were deposited onto functionalised glass slides and the influence of porogen, drying time, and monomer composition was studied. These MIP-functionalised glass electrodes were mounted into a customised 3D-printed flow cell, where changes in the liquid were either evaluated with a thermal device or using fluorescence bright field microscopy. Thermal analysis demonstrated that multiple MIP layers enhanced sensor specificity, with detection in the environmentally relevant range. The fluorescence bright field microscope investigations validated these results, showing an increase in the fluorescence intensity upon exposure of the MIP-functionalised glass slides to nafcillin solutions. These are promising results for developing a portable sensor device that can be deployed for antibiotics outside of a dedicated laboratory environment, especially if sensor design and fluorophore architecture are optimised.
KW - Molecularly Imprinted Polymers
KW - Fluorescence
KW - Antibiotics
KW - Heat-transfer Measurements
KW - Thin films
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540044
DO - https://doi.org/10.1039/D1MA00192B
VL - 2
IS - 15
SP - 5105
EP - 5115
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-54004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Homann, Christian
A1 - Peeters, Régis
A1 - Mirmajidi, Hana
A1 - Berg, Jessica
A1 - Fay, Michael
A1 - Rodrigues, Lucas Carvalho Veloso
A1 - Radicchi, Eros
A1 - Jain, Akhil
A1 - Speghini, Adolfo
A1 - Hemmer, Eva
T1 - Rapid microwave-assisted synthesis of morphology-controlled luminescent lanthanide-doped Gd2O2S nanostructures
N2 - Gadolinium oxysulfide (Gd2O2S) is an attractive material of demonstrated suitability for a variety of imaging applications, leveraging its magnetic, scintillating, and luminescent properties, particularly when doped with optically active lanthanide ions (Ln3+). For many of these applications, control over size and morphology at the nanoscale is crucial. This study demonstrates the rapid microwave-assisted Synthesis of colloidal Ln2O2S (Ln = Gd and dopants Yb, Er, Tb) nanostructures in as little as 20 min. Structural characterization using X-ray diffraction analysis (XRD), Raman spectroscopy, as well as Transmission electron microscopy (TEM), including elemental mapping via energy dispersive X-ray spectroscopy (EDS), unveiled the key role of elemental sulphur (S8) in the reaction mixtures for materials growth. By systematically varying the Ln-to-S ratio from 1 : 0.5 to 1 : 15, controlled morphologies ranging from triangular nanoplatelets to berry- and flower-like shapes were achieved. Doping with Er3+/Yb3+ endowed the nano-triangles with upconverting and near-infrared emitting properties. Tb3+-doped Gd2O2S exhibited the characteristic green Tb3+ emission under UV excitation, while also showing X-ray excited optical luminescence (XEOL), rendering the material interesting as a potential nano-scintillator.
KW - Upconversion
KW - Microwave-assisted synthesis
KW - Synthesis
KW - Fluorescence
KW - Nano
KW - Particle
KW - NIR
KW - XRD
KW - X-ray fluoressence
KW - Morphology control
KW - Raman
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647907
DO - https://doi.org/10.1039/D5TC01646K
SN - 2050-7526
VL - 13
IS - 35
SP - 18492
EP - 18507
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wen, Keqing
A1 - Gorbushina, Anna
A1 - Schwibbert, Karin
A1 - Bell, Jérémy
T1 - Microfluidic platform with precisely controlled hydrodynamic parameters and integrated features for generation of microvortices to accurately form and monitor biofilms in flow
N2 - Microorganisms often live in habitats characterized by fluid flow, and their adhesion to surfaces in industrial systems or clinical settings may lead to pipe clogging, microbially influenced corrosion, material deterioration, food spoilage, infections, and human illness. Here, a novel microfluidic platform was developed to investigate biofilm formation under precisely controlled (i) cell concentration, (ii) temperature, and (iii) flow conditions. The developed platform central unit is a single-channel microfluidic flow cell designed to ensure ultrahomogeneous flow and condition in its central area, where features, e.g., with trapping properties, can be incorporated. In comparison to static and macroflow chamber assays for biofilm studies, microfluidic chips allow in situ monitoring of biofilm formation under various flow regimes and have better environment control and smaller sample requirements. Flow simulations and experiments with fluorescent particles were used to simulate bacteria flow in the platform cell for calculating flow velocity and direction at the microscale level. The combination of flow analysis and fluorescent strain injection in the cell showed that microtraps placed at the center of the channel were efficient in capturing bacteria at determined positions and to study how flow conditions, especially microvortices, can affect biofilm formation. The microfluidic platform exhibited improved performances in terms of homogeneity and robustness for in vitro biofilm formation. We anticipate the presented platform to be suitable for broad, versatile, and high-throughput biofilm studies at the microscale level.
KW - Topographical pattern
KW - E. coli
KW - Fluorescence
KW - Bacteria trapping
KW - Particle velocimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610450
DO - https://doi.org/10.1021/acsbiomaterials.4c00101
SN - 2373-9878
VL - 10
IS - 7
SP - 4626
EP - 4634
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-61045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Ralf
A1 - Weigert, Florian
A1 - Lesnyak, V.
A1 - Leubner, S.
A1 - Lorenz, T.
A1 - Behnke, Thomas
A1 - Dubavik, A.
A1 - Joswig, J.-O.
A1 - Resch-Genger, Ute
A1 - Gaponik, N.
A1 - Eychmüller, A.
ED - Resch-Genger, Ute
ED - Schneider, Ralf
T1 - pH and concentration dependence of the optical properties of thiol-capped CdTe nanocrystals in water and D2O
N2 - The optical properties of semiconductor nanocrystals (SC NCs) are largely controlled by their size and surface chemistry, i.e., the chemical composition and thickness of inorganic passivation shells and the chemical nature and number of surface ligands as well as the strength of their bonds to surface atoms.
The latter is particularly important for CdTe NCs, which – together with alloyed CdₓHg₁₋ₓTe – are the only SC NCs that can be prepared in water in high quality without the need for an additional inorganic passivation shell. Aiming at a better understanding of the role of stabilizing ligands for the control of the application-relevant fluorescence features of SC NCs, we assessed the influence of two of the most commonly used monodentate thiol ligands, thioglycolic acid (TGA) and mercaptopropionic acid (MPA),
on the colloidal stability, photoluminescence (PL) quantum yield (QY), and PL decay behavior of a set of CdTe NC colloids. As an indirect measure for the strength of the coordinative bond of the ligands to SC NC surface atoms, the influence of the pH (pD) and the concentration on the PL properties of these colloids was examined in water and D₂O and compared to the results from previous dilution studies with a set of thiol-capped Cd₁₋ₓHgₓTe SC NCs in D₂O. As a prerequisite for these studies, the number of surface ligands was determined photometrically at different steps of purification after SC NC synthesis with Ellman’s test.
Our results demonstrate ligand control of the pH-dependent PL of these SC NCs, with MPA-stabilized CdTe NCs being less prone to luminescence quenching than TGA-capped ones. For both types of CdTe colloids, ligand desorption is more pronounced in H₂O compared to D₂O, underlining also the role of hydrogen bonding and solvent molecules.
KW - Quantum dots
KW - Fluorescence
KW - Ligand analysis
KW - Nano particles
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371253
DO - https://doi.org/10.1039/c6cp03123d
VL - 18
IS - 28
SP - 19083
EP - 19092
PB - RSC
CY - Cambridge
AN - OPUS4-37125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Pérez-Padilla, Víctor
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Ratiometric detection of perfluoroalkyl carboxylic acids using dual fluorescent nanoparticles and a miniaturised microfluidic platform
N2 - The widespread contamination of soil and water with perfluoroalkyl substances (PFAS) has caused considerable societal and scientific concern. Legislative measures and an increased need for remediation require effective on-site analytical methods for PFAS management. Here we report on the development of a green-fluorescent guanidine-BODIPY indicator monomer incorporated into a molecularly imprinted polymer (MIP) for the selective detection of perfluorooctanoic acid (PFOA). Complexation of PFOA by the indicator, which is mediated by concerted protonation-induced ion pairing-assisted hydrogen bonding, significantly enhances fluorescence in polar organic solvents. The MIP forms as a thin layer on silica nanoparticles doped with tris(bipyridine)ruthenium(II) chloride, which provides an orange emission signal as internal reference, resulting in low measurement uncertainties. Using a liquid-liquid extraction protocol, this assay enables the direct detection of PFOA in environmental water samples and achieves a detection limit of 0.11 µM. Integration into an opto-microfluidic system enables a compact and user-friendly system for detecting PFOA in less than 15 minutes.
KW - PFAS
KW - Molecular imprinting
KW - Microfluidics
KW - Fluorescence
KW - Onsite assay
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650270
DO - https://doi.org/10.1038/s41467-025-66872-9
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-65027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oskoei, Párástu
A1 - Afonso, Rúben
A1 - Bastos, Verónica
A1 - Nogueira, João
A1 - Keller, Lisa-Marie
A1 - Andresen, Elina
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Daniel-da-Silva, Ana L.
A1 - Oliveira, Helena
T1 - Upconversion Nanoparticles with Mesoporous Silica Coatings for Doxorubicin Targeted Delivery to Melanoma Cells
N2 - Melanoma is one of the most aggressive skin cancers and requires innovative therapeutic strategies to overcome the limitations of conventional therapies. In this work, upconversion nanoparticles coated with mesoporous silica and functionalized with folic acid (UCNP@mSiO2-FA) were developed as a targeted nanocarrier system for the delivery of doxorubicin (DOX). The UCNPs were synthesized via thermal decomposition, coated with mesoporous silica shells, and functionalized with folic acid (FA) to enable receptor-mediated targeting. DOX was then loaded into the mesoporous silica coating by adsorption, yielding UCNP@mSiO2-FA-DOX. The different UCNPs were characterized for size, composition, colloidal stability, and loading and release of DOX. This comprehensive physicochemical characterization confirmed a high DOX loading efficiency and a slightly increased drug release under acidic conditions, mimicking the tumour microenvironment. In vitro assays using four melanoma cell lines (A375, B16-F10, MNT-1, and SK-MEL-28) revealed an excellent biocompatibility of UCNP@mSiO2-FA and a significantly higher cytotoxicity of UCNP@mSiO2-FA-DOX compared to unloaded UCNPs, in a dose-dependent manner. Cell cycle analysis demonstrated G2/M phase arrest after treatment with UCNP@mSiO2-FA-DOX, confirming its antiproliferative effect. Overall, UCNP@mSiO2-FA-DOX represents a promising nanoplatform for targeted melanoma therapy, combining active tumour targeting and enhanced anticancer efficacy.
KW - Fluorescence
KW - Synthesis
KW - Nano
KW - Particle
KW - Silica
KW - Cell
KW - Uptake
KW - Drug
KW - Characterization
KW - DOX
KW - Imaging
KW - Toxicity
KW - Release
KW - pH
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653596
DO - https://doi.org/10.3390/molecules31010074
SN - 1420-3049
VL - 31
IS - 1
SP - 1
EP - 18
PB - MDPI AG
AN - OPUS4-65359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodriguez, Santiago
A1 - Kumanski, Sylvain
A1 - Ayed, Zeineb
A1 - Fournet, Aurélie
A1 - Bouanchaud, Charlène
A1 - Sagar, Amin
A1 - Allemand, Frédéric
A1 - Baulin, Vladimir A.
A1 - Resch‐Genger, Ute
A1 - Cortés, Juan
A1 - Sibille, Nathalie
A1 - Chirot, Fabien
A1 - Wegner, Karl David
A1 - Antoine, Rodolphe
A1 - Le Guével, Xavier
A1 - Bernadó, Pau
T1 - Programming the Optoelectronic Properties of Atomically Precise Gold Nanoclusters Using the Conformational Landscape of Intrinsically Disordered Proteins
N2 - The rational design of hybrid nanomaterials with precisely controlled properties remains a central challenge in materials science. While atomically precise gold nanoclusters (Au‐NCs) offer molecule‐like control over a metallic core, tuning their optoelectronic behavior via surface engineering is often empirically driven. Here, we establish a design principle by demonstrating that the conformational landscape of intrinsically disordered proteins (IDP) can be used as a programmable scaffold to rationally modulate the photophysical properties of a covalently bound Au‐NC. We synthesized a series of bioconjugates between Au 25 nanoclusters and bioengineered IDPs containing a variable number of cysteine anchoring points. A combination of mass spectrometry, small‐angle X‐ray scattering, and modeling on the conjugates indicates that increasing the number of covalent anchors systematically restricts the conformational ensemble, inducing a progressively more compact protein shell around nanoclusters. This structural rigidification at the interface directly translates into a 15‐fold enhancement of the Au‐NC near‐infrared photoluminescence and a six‐fold increase in its average lifetime. Our findings demonstrate that the conformational plasticity of IDPs and the capacity to engineer them can be harnessed as a molecular tuning knob, moving to a new regime of programmable soft‐matter control over the properties of quantum‐confined nanomaterials for tailored biotechnological applications.
KW - Fluorescence
KW - Custer
KW - Nano
KW - Advanced material
KW - Characterization
KW - Fluorescence quantum yield
KW - Integrating sphere spectroscopy
KW - Thiol ligands
KW - Gold
KW - Surface chemistry
KW - SWIR
KW - Mass spectrometry
KW - Protein
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655086
DO - https://doi.org/10.1002/chem.202502991
SN - 0947-6539
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-65508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shovo, Redoy Gazi
A1 - Thünemann, Andreas
A1 - Katcharava, Zviadi
A1 - Marinvo, Anja
A1 - Hoppe, Richard
A1 - Woltersdorf, Georg
A1 - Du, Mengxue
A1 - Androsch, Rene
A1 - de Souza e Silva, Juliana Martins
A1 - Busse, Karste
A1 - Binder, Wolfgang H.
T1 - Generating Tagged Micro- and Nanoparticles of Poly(ethylene furanoate) and Poly(ethylene terephthalate) as Reference Materials
N2 - Detecting nanoplastic particles in environmental samples and biological tissues remains a significant challenge, especially in view of newly emerging polymers, not yet commercially exploited. Fluorescent labeling provides a tagging strategy to overcome this limitation by reducing the detection limit of individual particles, especially for small-sized particles. We present a method for producing labeled nanoparticles (NP/MP) of poly(ethylene terephthalate) (PET) and poly(ethylene furanoate) (PEF), tagged with Alexa Fluor 633 or Alexa Fluor 647. Our preparations used mechanical grinding or solvent-based approaches (confined impinging jet mixing, ((CIJ, precipitation), generating particles with hydrodynamic diameters of 200–700 nm, displaying long-term stability in water of up to 57 days. Stable suspensions with concentrations of the particles ranging from 10 µg/mL (surfactant-free, by solvent mixing) to 5.88 mg/mL (precipitation, containing surfactant) were generated with zeta-potentials from −5 to −50 mV. Characterization of the nanoparticles by SEC, DSC, and XRD showed no significant changes in molecular weight, thermal behavior, or crystallinity via the solvent-based methods, compared to the pristine polymer, highlighting their suitability for producing standardized nanoparticle dispersions. Fluorescence spectroscopy of the Alexa-dye-labeled particles confirmed the successful incorporation of the Alexa dyes, so improving monitoring of their biological profiles of the PEF-MP/NPs. s-SNOM (near field imaging) could identify individual PEF-particles sized ∼200 nm by direct imaging.
KW - Reference Materials
KW - Nanoplastics
KW - Microplastics
KW - Polymer
KW - Fluorescence
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655531
DO - https://doi.org/10.1002/marc.202500839
SN - 1521-3927
VL - 47
IS - 4
SP - 1
EP - 11
PB - Wiley VHC-Verlag
CY - Weinheim
AN - OPUS4-65553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prakash, Swayam
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Rapid Onsite Detection of Fecal Contamination in Water Using a Portable Fluorometric Assay
N2 - Fecal pollution in water poses significant health risks, especially when contaminated sources are used for drinking and food production. Traditional water quality testing methods are expensive, slow, and require skilled personnel, limiting their accessibility. This work addresses these issues by developing a portable fluorometric assay for the detection of the fecal indicator pigment urobilin (UB). The assay uses silane-functionalized glass fiber strips impregnated with zinc chloride, providing a ‘drop-&-detect’ approach with enhanced fluorescence response mediated by the unique complexation properties of ZnCl2 and UB. This approach allows for the detection of UB at sub-nanomolar concentrations in less than 1 min using a 3D-printed setup with miniaturized optical components powered by a smartphone with its camera as a detector. The results validated with a benchtop fluorometer show the effectiveness of this method. The successful application of this userfriendly, rapid, and sensitive assay to real water samples from three rivers and the influx and efflux of a wastewater treatment plant advances field-based water quality monitoring, meets the WHO’s ASSURED criteria, and supports progress toward the global clean water and sanitation goals.
KW - Fecal pigment
KW - Fluorescence
KW - Signal amplification
KW - Surface chemistry
KW - Water quality testing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655543
DO - https://doi.org/10.1021/acssensors.5c03922
SN - 2379-3694
VL - 11
SP - 1
EP - 9
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-65554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kossatz, Philipp
A1 - Mezhov, Alexander
A1 - Andresen, Elina
A1 - Prinz, Carsten
A1 - Schmidt, Wolfram
A1 - Resch-Genger, Ute
T1 - Assessing the Applicability of Lanthanide-Based Upconverting Nanoparticles for Optically Monitoring Cement Hydration and Tagging Building Materials
N2 - Chemically stable, lanthanide-based photon upconversion micro- and nanoparticles (UCNPs) with their characteristic multicolor emission bands in the ultraviolet (UV), visible (vis), near-infrared (NIR), and short-wave infrared (SWIR) arepromising optical reporters and barcoding tags. To assess the applicability of UCNPs for the monitoring of early stage cement hydration processes and as authentication tags for cementitious materials, we screened the evolution of the luminescence of Selfmade core-only NaYF4:Yb,Er UCNPs and commercial μm-sized Y2O2S:Yb,Er particles during the first stages of cement hydration, which largely determines the future properties of the hardened material. Parameters explored from the UCNP side included particle size, morphology, surface chemistry or coating, luminescence properties, and concentration in different cement mixtures. From the cement side, the influence of the mineral composition of the cement matrix was representatively examined for ordinary Portland cement (OPC) and its constituents tricalcium aluminate (C3A), tricalcium silicate (C3S), and gypsum at different water to cement ratios. Based on reflection and luminescence measurements, enabling online monitoring, which were complemented by XRD and isothermal heat-flow calorimetric measurements to determine whether the incorporation of these particles could impair cement hydration processes, well suited lanthanide particle reporters could be identified as well as application conditions. In addition, thereby the reporter influence on cement hydration kinetics could be minimized while still preserving a high level of information content. The best performance for the luminescence probing of changes during early stage cement hydration processes was observed for 25 nm-sized oleate (OA)-coated UCNPs added in a concentration of 0.1 wt %. Higher UCNP amounts of 1.0 wt % delayed cement hydration processes size- and surface coatingspecifically in the first 24 h. Subsequent luminescence stability screening studies performed over a period of about one year support the applicability of UCNPs as optical authentication tags for construction materials.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Quantum yield
KW - NIR
KW - Mechanism
KW - Characterization
KW - XRD
KW - Calorimetry
KW - Advanced material
KW - Cement
KW - Monitoring
KW - Surface
KW - Size
KW - Lifetime
KW - Barcode
KW - Lanthanide
KW - Upconversion
KW - Encoding
KW - Method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638318
DO - https://doi.org/10.1021/acsomega.5c02236
SN - 2470-1343
VL - 10
IS - 29
SP - 31587
EP - 31599
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-63831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ren, J.
A1 - Weigert, Florian
A1 - Weber, F.
A1 - Wang, Y.
A1 - Choudhury, S.
A1 - Xiao, J.
A1 - Lauermann, I.
A1 - Resch-Genger, Ute
A1 - Bande, A.
A1 - Petit, T.
ED - Petit, Tristan
T1 - Influence of surface chemistry on optical, chemical and electronic properties of blue luminescent carbon dots
N2 - Carbon dots have attracted much attention due to their unique optical, chemical and electronic properties enabling a wide range of applications. The properties of carbon dots can be effectively adjusted through modifying their chemical composition. However, a major challenge remains in understanding the core and surface contributions to optical and electronic transitions. Here, three blue luminescent carbon dots with carboxyl, amino and hydroxyl groups were comprehensively characterized by UV-vis absorption and emission spectroscopy, synchrotron-based X-ray spectroscopy, and infrared spectroscopy. The influence of the surface functionality on their fluorescence was probed by pH-dependent photoluminescence measurements. Moreover, the hydrogen bonding interactions between water and the surface groups of carbon dots were characterized by infrared spectroscopy. Our results show that both core and surface electronic states of blue luminescent carbon dots contribute to electronic acceptor levels while the chemical nature of the surface groups determines the hydrogen bonding behavior of the carbon dots. This comprehensive spectroscopic study demonstrates that the surface chemistry has a profound influence on the electronic configuration and surface–water interaction of carbon dots, thus affecting their photoluminescence properties.
KW - Quantum dots
KW - Spectroscopy
KW - UV Vis
KW - Fluorescence
KW - Surface chemistry
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472325
DO - https://doi.org/10.1039/c8nr08595a
SN - 2040-3372
VL - 11
IS - 4
SP - 2056
EP - 2064
PB - RSC
AN - OPUS4-47232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Descalzo, Ana B.
A1 - Ashokkumar, Pichandi
A1 - Shen, Z.
A1 - Rurack, Knut
T1 - On the Aggregation Behaviour and Spectroscopic Properties of Alkylated and Annelated BoronDipyrromethene (BODIPY) Dyes in Aqueous Solution
N2 - The tendency of boron-dipyrromethene (BODIPY) dyes to associate in water is well known, and usually a cause for inferior fluorescence properties. Synthetic efforts to chemically improve BODIPYs’ water solubility and minimize this problem have been numerous in the past. However, a deeper understanding of the phenomena responsible for fluorescence quenching is still required. Commonly, the spectroscopic behaviour in aqueous media has been attributed to aggregate or excimer formation, with such works often centring on a single BODIPY family. Herein, we provide an integrating discussion including very diverse types of BODIPY dyes. Our studies revealed that even subtle structural changes can distinctly affect the association behaviour of the fluorophores in water, involving different photophysical processes. The palette of behaviour found ranges from unperturbed emission, to the formation of H or J aggregates and excimers, to the involvement of tightly bound, preformed excimers. These results are a first step to a more generalized understanding of spectroscopic properties vs. structure, facilitating future molecular design of BODIPYs, especially as probes for biological applications.
KW - Aggregates
KW - BODIPY
KW - Excimers
KW - Fluorescence
KW - Photophysics
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497771
DO - https://doi.org/10.1002/cptc.201900235
SN - 2367-0932
VL - 4
IS - 2
SP - 120
EP - 131
PB - WILEY-VCH
CY - Weinheim
AN - OPUS4-49777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, H.
A1 - Song, W.
A1 - Gröninger, Delia
A1 - Zhang, L.
A1 - Lu, Y.
A1 - Chan, K. S.
A1 - Zhou, Z.
A1 - Rurack, Knut
A1 - Shen, Z.
T1 - Real-time monitoring of newly acidified organelles during autophagy enabled by reaction-based BODIPY dyes
N2 - Real-time monitoring of newly acidified organelles during autophagy in living cells is highly desirable for a better understanding of intracellular degradative processes. Herein, we describe a reaction-based boron dipyrromethene (BODIPY) dye containing strongly electron-withdrawing diethyl 2-cyanoacrylate groups at the α-positions. The probe exhibits intense red fluorescence in acidic organelles or the acidified cytosol while negligible fluorescence in other regions of the cell. The underlying mechanism is a nucleophilic reaction at the central meso-carbon of the indacene core, resulting in the loss of π-conjugation entailed by dramatic spectroscopic changes of more than 200 nm between its colorless, non-fluorescent leuco-BODIPY form and its red and brightly emitting form. The reversible transformation between red fluorescent BODIPY and leuco-BODIPY along with negligible cytotoxicity qualifies such dyes for rapid and direct intracellular lysosome imaging and cytosolic acidosis detection simultaneously without any washing step, enabling the real-time monitoring of newly acidified organelles during autophagy.
KW - Autophagy
KW - BODIPY
KW - Fluorescence
KW - Lysosome
KW - Real-time imaging
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498358
UR - https://www.nature.com/articles/s42003-019-0682-1
DO - https://doi.org/10.1038/s42003-019-0682-1
SN - 23993642
VL - 2
SP - 442
PB - Nature Research
CY - London
AN - OPUS4-49835
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gharaati, S.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Weigert, Florian
A1 - Resch-Genger, Ute
A1 - Heinze, K.
T1 - Triplet–Triplet Annihilation Upconversion in a MOF with AcceptorFilled Channels
N2 - In summary, we report a highly modular solid TTA-UC system comprising of a crystalline, thermally stable PCN222(Pd) MOF with CA-coated MOF channels and with a DPA annihilator embedded in a solution-like environment in the MOF channels. This solid material displays blue upconverted delayed emission with a luminescence lifetime of 373 us, a threshold value of 329 mW*cm-2 and a triplet–triplet energy transfer efficiency of 82%. This optical application adds another facet to the versatile chemistry of PCN-222 MOFs. The design concept is also applicable to other TTA-UC pairs and enables tuning of the UCL color, for example, by replacing DPA with other dyes as exemplarily shown for 2,5,8,11-tetra-tert-butyl-perylene, that yields UCL at 450 nm. Current work aims to reduce the oxygen sensitivity and to increase the retention of the trapped annihilators in organic environments, for example, by tuning the chain length of the carboxylic acid and by coating the MOF surface. In addition, the TTA-UC efficiency will be further enhanced by reducing the reabsorption of the UC emission caused by Pd(TCPP) and by optimizing the sensitizer/annihilator interface.
KW - Porphyrin
KW - Method
KW - MOF
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Oxygen sensitive
KW - Single molecule
KW - DPA
KW - Lifetime
KW - Upconverstion
KW - Quantum yield
KW - Triplet-triplet annihilation
KW - Sensitization
KW - Energy transfer
KW - NMR
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500580
DO - https://doi.org/10.1002/chem.201904945
VL - 26
IS - 5
SP - 1003
EP - 1007
PB - Wiley-VCH Verlag
CY - Weinheim
AN - OPUS4-50058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gotor, Raúl
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Tailored fluorescent solvatochromic test strips for quantitative on-site detection of gasoline fuel adulteration
N2 - Gasoline adulteration is a frequent problem world-wide, because of the chance of quick, maximized profits. However, addition of cheaper ethanol or hydrocarbons like kerosene does not only result in economic damage but also poses problems for vehicles and the environment. To enable law enforcement forces, customers or enterprises to uncover such a fraudulent activity directly upon suspicion and without the need to organize for sampling and laboratory analysis, we developed a simple strip-based chemical test. Key to the favorable performance was the dedicated materials tailoring, which led to test strips that consisted of a cellulose support coated with silica, passivated with hexamethyldisilazane and functionalized covalently with a molecular probe. The probe fluoresces brightly across a broad solvent polarity range, enabling reliable quantitative measurements and data analysis with a conventional smartphone. The assays showed high reproducibility and accuracy, allowing not only for the detection of gasoline adulteration but also for the on-site monitoring of the quality of commercial E10 gasoline.
KW - Gasoline
KW - Adulteration
KW - Test strips
KW - Benzin
KW - Teststreifen
KW - Fluorescence
KW - Cellulose
KW - Zellulose
KW - Fluoreszenz
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479231
UR - https://pubs.rsc.org/en/content/articlelanding/2019/tc/c8tc04818e
DO - https://doi.org/10.1039/C8TC04818E
SN - 2050-7526
VL - 7
IS - 8
SP - 2250
EP - 2256
PB - Royal Society of Chemistry
CY - London, UK
AN - OPUS4-47923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bartelmeß, Jürgen
A1 - Valderrey, Virginia
A1 - Rurack, Knut
T1 - Development of a “Turn-on” Fluorescent Probe-Based Sensing System for Hydrogen Sulfide in Liquid and Gas Phase
N2 - A “turn-on” fluorescence sensing system based on a BODIPY-cobaloxime complex for the detection of H2S in liquid and gas phase was developed. To that aim, two cobaloxime complexes bearing an axial pyridyl-BODIPY ligand were initially evaluated as sensitive fluorescent HS− indicators in aqueous solution. The sensing mechanism involves the selective substitution of the BODIPY ligand by the HS− anion at the cobalt center, which is accompanied by a strong fluorescence enhancement. The selection of a complex with an ideal stability and reactivity profile toward HS− relied on the optimal interaction between the cobalt metal-center and two different pyridyl BODIPY ligands. Loading the best performing BODIPY-cobaloxime complex onto a polymeric hydrogel membrane allowed us to study the selectivity of the probe for HS− against different anions and cysteine. Successful detection of H2S by the fluorescent “light-up” membrane was not only accomplished for surface water but could also be demonstrated for relevant H2S concentrations in gas phase.
KW - Sulfide sensing
KW - Fluorescence
KW - BODIPYs
KW - Cobaloxime complex
KW - Gas sensing
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492186
DO - https://doi.org/10.3389/fchem.2019.00641
SN - 2296-2646
VL - 7
SP - Art. Nr. 641
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-49218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huang, J.
A1 - Tarábek, J.
A1 - Kulkarni, R.
A1 - Wang, Cui
A1 - Dračínský, M.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Resch-Genger, Ute
A1 - Bojdys, M. J.
T1 - A π-conjugated, covalent phosphinine framework
N2 - Structural modularity of polymer frameworks is a key advantage of covalent organic polymers, however, only C, N, O, Si and S have found their way into their building blocks so far. Here, we expand the toolbox available to polymer and materials chemists by one additional nonmetal, phosphorus. Starting with a building block that contains a λ⁵‐phosphinine (C₅P) moiety, we evaluate a number of polymerisation protocols, finally obtaining a π‐conjugated, covalent phosphinine‐based framework (CPF‐1) via Suzuki‐Miyaura coupling. CPF‐1 is a weakly porous polymer glass (72.4 m2 g‐1 N2 BET at 77 K) with green fluorescence (λmax 546 nm) and extremely high thermal stability. The polymer catalyzes hydrogen evolution from water under UV and visible light irradiation without the need for additional co‐catalyst at a rate of 33.3 μmol h‐¹ g‐¹. Our results demonstrate for the first time the incorporation of the phosphinine motif into a complex polymer framework. Phosphinine‐based frameworks show promising electronic and optical properties that might spark future interest in their applications in light‐emitting devices and heterogeneous catalysis.
KW - Phosphinine
KW - Fully aromatic frameworks
KW - Suzuki-Miyaura coupling
KW - Polymers
KW - Fluorescence
KW - Small-angle scattering
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485330
DO - https://doi.org/10.1002/chem.201900281
SP - 2
EP - 10
PB - Wiley VCH-Verlag
CY - Weinheim
AN - OPUS4-48533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Brunet, G.
A1 - Marin, R.
A1 - Monk, Melissa-Jane
A1 - Galico, D. A.
A1 - Sigoli, F. A.
A1 - Suturina, E. A.
A1 - Hemmer, E.
A1 - Murugesu, M.
T1 - Exploring the dual functionality of an Ytterbium complex for luminescence thermometry and slow magnetic relaxation†
N2 - We present a comprehensive investigation of the magnetic and optical properties of an ytterbium complex, which combines two desirable and practical features into a single molecular system. Based upon YbIII Ions that promote near-infrared optical activity and a chemical backbone that is ideal for an in-depth understanding of the magnetic behaviour, we have designed a multifunctional opto-magnetic species that operates as a luminescent thermometer and as a single-molecule magnet (SMM). Our magnetic investigations, in conjunction with ab initio calculations, reveal one of the highest energy barriers reported for an YbIII-based complex. Moreover, we correlate this anisotropic barrier with the Emission spectrum of the compound, wherein we provide a complete assignment of the energetic profile of the complex. Such studies lay the foundation for the design of exciting multi-faceted materials that are able to retain information at the single-molecule level and possess built-in thermal self-monitoring capabilities.
KW - Magnetic
KW - Fluorescence
KW - NIR
KW - Temperature
KW - Dual sensing
KW - Sensor
KW - Yb(III) complex
KW - Lanthanide
KW - Quantum yield
KW - Quality assurance
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486659
DO - https://doi.org/10.1039/c9sc00343f
VL - 10
IS - 28
SP - 6799
EP - 6808
PB - Royal Society of Chemistry
AN - OPUS4-48665
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Wang, Shu
A1 - Radnik, Jörg
A1 - You, Yi
A1 - Resch-Genger, Ute
T1 - Assessing the protective effects of different surface coatings on NaYF4:YB3+, Er3+, upconverting nanoparticles in buffer and DMEM
N2 - We studied the dissolution behavior of β NaYF4:Yb(20%), Er(2%) UCNP of two different sizes in biologically relevant media i.e., water (neutral pH), phosphate buffered saline (PBS), and Dulbecco’s modified Eagle medium (DMEM) at different temperatures and particle concentrations. Special emphasis was dedicated to assess the influence of different surface functionalizations, particularly the potential of mesoporous and microporous silica shells of different thicknesses for UCNP stabilization and protection. Dissolution was quantified electrochemically using a fluoride ion selective electrode (ISE) and by inductively coupled plasma optical emission spectrometry (ICP OES). In addition, dissolution was monitored fluorometrically. These experiments revealed that a thick microporous silica shell drastically decreased dissolution. Our results also underline the critical influence of the chemical composition of the aqueous environment on UCNP dissolution. In DMEM, we observed the formation of a layer of adsorbed molecules on the UCNP surface that protected the UCNP from dissolution and enhanced their fluorescence. Examination of this layer by X ray photoelectron spectroscopy (XPS) and mass spectrometry (MS) suggested that mainly phenylalanine, lysine, and glucose are adsorbed from DMEM. These findings should be considered in the future for cellular toxicity studies with UCNP and other nanoparticles and the design of new biocompatible surface coatings.
KW - Fluorescence
KW - Lifetime
KW - Method
KW - Quantification
KW - Stability
KW - Coating
KW - Surface chemistry
KW - Lanthanide
KW - Fluoride
KW - Electrochemistry
KW - ICP-OES
KW - Upconversion
KW - Nano
KW - Particle
KW - Aging
KW - Quality assurance
KW - Mass spectrometry
KW - XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515984
DO - https://doi.org/10.1038/s41598-020-76116-z
SN - 2045-2322
VL - 10
IS - 1
SP - 19318-1
EP - 19318-11
PB - Springer Nature
CY - London
AN - OPUS4-51598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Rajotte, Isabelle
A1 - Thibeault, Marie-Pier
A1 - Sander, Philipp C.
A1 - Kodra, Oltion
A1 - Lopinski, Gregory
A1 - Radnik, Jörg
A1 - Johnston, Linda J.
A1 - Brinkmann, Andreas
A1 - Resch-Genger, Ute
T1 - Quantifying surface groups on aminated silica nanoparticles of different size, surface chemistry, and porosity with solution NMR, XPS, optical assays, and potentiometric titration
N2 - We assessed the quantification of surface amino functional groups (FGs) for a large set of commercial and custom-made aminated silica nanoparticles (SiO2 NPs) with sizes of 20–100 nm, prepared with different sol–gel routes, different amounts of surface amino FGs, and different porosity with four methods providing different, yet connected measurands in a bilateral study of two laboratories, BAM and NRC, with the overall aim to develop standardizable measurements for surface FG quantification. Special emphasis was dedicated to traceable quantitative magnetic resonance spectroscopy (qNMR) performed with dissolved SiO2 NPs. For the cost efficient and automatable screening of the amount of surface amino FGs done in a first step of this study, the optical fluorescamine assay and a potentiometric titration method were utilized by one partner, i.e., BAM, yielding the amount of primary amino FGs accessible for the reaction with a dye precursor and the total amount of (de)protonatable FGs. These measurements, which give estimates of the minimum and maximum number of surface amino FGs, laid the basis for quantifying the amount of amino silane molecules with chemo-selective qNMR with stepwise fine-tuned workflows, involving centrifugation, drying, weighting, dissolution, measurement, and data evaluation steps jointly performed by BAM and NRC. Data comparability and relative standard deviations (RSDs) obtained by both labs were used as quality measures for method optimization and as prerequisites to identify method-inherent limitations to be later considered for standardized measurement protocols. Additionally, the nitrogen (N) to silicon (Si) ratio in the near-surface region of the SiO2 NPs was determined by both labs using X-ray photoelectron spectroscopy (XPS), a well established surface sensitive analytical method increasingly utilized for microparticles and nano-objects which is currently also in the focus of international standardization activities. Overall, our results underline the importance of multi-method characterization studies for quantifying FGs on NMs involving at least two expert laboratories for effectively identifying sources of uncertainty, validating analytical methods, and deriving NM structure–property relationships.
KW - Advanced Materials
KW - Amino Groups
KW - Calibration
KW - Characterization
KW - Functional groups
KW - Method Comparison
KW - Nano Particle
KW - Validation
KW - XPS
KW - Optical Assay
KW - Quantification
KW - Surface Analysis
KW - Reference Materials
KW - Synthesis
KW - Fluorescence
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649992
DO - https://doi.org/10.1039/d5na00794a
VL - 7
IS - 21
SP - 6888
EP - 6900
PB - Royal Society of Chemistry
AN - OPUS4-64999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Siebler, Daniel
A1 - Rohwetter, Philipp
A1 - Brusenbach, R.
A1 - Plath, R.
T1 - Optical-only detection of partial discharge with fluorescent polymer optical fiber sensors
N2 - This paper reflects recent progress in the field of fluorescent polymer optical fiber sensors (F-POF) for partial discharge (PD) detection in high voltage (HV) cable accessories using optical-only PD detection by coincidence single photon counting. In experiments with artificial PD sources these sensors show the ability to detect optical emissions from picocoulomb-level PDs in a real-scale model of a translucent high voltage cable accessory. False positives (caused by detector noise) are efficiently suppressedwhile maintaining sufficient sensitivity,even when the sensor is located in an unfavorable position.
T2 - EUROSENSORS 2015
CY - Freiburg, Germany
DA - 06.09.2015
KW - Partial discharge
KW - Silicone rubber
KW - High voltage cable accessories
KW - Polymer optical fiber POF
KW - Fluorescence
KW - Coincidence
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337881
DO - https://doi.org/10.1016/j.proeng.2015.08.711
SN - 1877-7058
VL - 120
SP - 845
EP - 848
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-33788
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Meermann, Björn
A1 - Koch, Matthias
A1 - Weller, Michael G.
T1 - Editorial: Analytical methods and applications in materials and life sciences
N2 - Current trends in materials and life sciences are flanked by the need to push detection limits to single molecules or single cells, enable the characterization of increasingly complex matrices or sophisticated nanostructures, speed up the time of analysis, reduce instrument complexity and costs, and improve the reliability of data. This requires suitable analytical tools such as spectroscopic, separation and imaging techniques, mass spectrometry, and hyphenated techniques as well as sensors and their adaptation to application-specific challenges in the environmental, food, consumer product, health sector, nanotechnology, and bioanalysis. Increasing concerns about health threatening known or emerging pollutants in drinking water, consumer products, and food and about the safety of nanomaterials led to a new awareness of the importance of analytical sciences. Another important driver in this direction is the increasing demand by legislation, particularly in view of the 17 sustainable development goals by the United Nations addressing clean energy, industry, and innovation, sustainable cities, clean water, and responsible consumption and production. In this respect, also the development of analytical methods that enable the characterization of material flows in production processes and support recycling concepts of precious raw materials becomes more and more relevant. In the future, this will provide the basis for greener production in the chemical industry utilizing recycled or sustainable starting materials.
This makes analytical chemistry an essential player in terms of the circular economy helping to increase the sustainability of production processes. In the life sciences sector, products based on proteins, such as therapeutic and diagnostic antibodies, increase in importance. These increasingly biotechnologically produced functional biomolecules pose a high level of complexity of matrix and structural features that can be met only by highly advanced methods for separation, characterization, and detection. In addition, metrological traceability and target definition are still significant challenges for the future, particularly in the life sciences.
However, innovative reference materials as required for the health and food sector and the characterization of advanced materials can only be developed when suitable analytical protocols are available. The so-called reproducibility crisis in sciences underlines the importance of improved measures of quality control for all kinds of measurements and material characterization. This calls for thorough method validation concepts, suitable reference materials, and regular interlaboratory comparisons of measurements as well as better training of scientists in analytical sciences.
The important contribution of analytical sciences to these developments is highlighted by a broad collection of research papers, trend articles, and critical reviews from these different application fields. Special emphasis is dedicated to often-overlooked quality assurance and reference materials.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - Analysis
KW - Life sciences
KW - Analytical sciences
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Nanoparticle
KW - Sensor
KW - Material sciences
KW - Pollutant
KW - Environment
KW - Method
KW - Limit of detection
KW - 150th anniversary
KW - ABC
KW - BAM
KW - Collection
KW - Editorial
KW - Special issue
KW - Bundesanstalt für Materialforschung und -prüfung
KW - Jahrestag
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550720
DO - https://doi.org/10.1007/s00216-022-04082-8
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - Topical collection: Analytical methods and applications in the materials and life sciences
SP - 4267
EP - 4268
PB - Springer
CY - Berlin
AN - OPUS4-55072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Martin
A1 - Weller, Michael G.
T1 - Antibody screening by microarray technology - Direct identification of selective high-affinity clones
N2 - The primary screening of hybridoma cells is a time-critical and laborious step during the development of monoclonal antibodies. Often, critical errors occur in this phase, which supports the notion that the generation of monoclonal antibodies with hybridoma technology is difficult to control and hence, a risky venture. We think that it is crucial to improve the screening process to eliminate most of the critical deficits of the conventional approach. With this new microarray-based procedure, several advances could be achieved: Selectivity for excellent binders, high-throughput, reproducible signals, avoidance of misleading avidity (multivalency) effects, and performance of simultaneous competition experiments. The latter can also be used to select clones of desired cross-reactivity properties. In this paper, a model system with two excellent clones against carbamazepine, two weak clones, and blank supernatant containing fetal bovine serum was designed to examine the effectiveness of the new system. The excellent clones could be detected largely independent of the immunoglobulin G (IgG) concentration, which is usually unknown during the clone screening since the determination and subsequent adjustment of the antibody concentration are not feasible in most cases. Furthermore, in this approach, the enrichment, isolation, and purification of IgG for characterization is not necessary. Raw cell culture supernatant can be used directly, even when fetal calf serum (FCS) or other complex media is used. In addition, an improved method for the oriented antibody-immobilization on epoxy-silanized slides is presented. Based on the results of this model system with simulated hybridoma supernatants, we conclude that this approach should be preferable to most other protocols leading to many false positives, causing expensive and lengthy elimination steps to weed out the poor clones.
KW - ELISA
KW - Immunoassay
KW - Microarray
KW - Lab-on-a-chip
KW - Miniaturization
KW - Aautomatisation
KW - HTS
KW - High-throughput
KW - Screening
KW - Fluorescence
KW - Label
KW - Hybridoma
KW - Inhibition
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503361
DO - https://doi.org/10.3390/antib9010001
SN - 2073-4468
VL - 9
IS - 1
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-50336
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reinmuth-Selzle, K.
A1 - Tchipilov, Teodor
A1 - Backes, A. T.
A1 - Tscheuschner, Georg
A1 - Tang, K.
A1 - Ziegler, K.
A1 - Lucas, K.
A1 - Pöschl, U.
A1 - Fröhlich-Nowoisky, J.
A1 - Weller, Michael G.
T1 - Determination of the protein content of complex samples by aromatic amino acid analysis, liquid chromatography-UV absorbance, and colorimetry
N2 - Fast and accurate determination of the protein content of a sample is an important and non-trivial task of many biochemical, biomedical, food chemical, pharmaceutical, and environmental research activities. Different methods of total protein determination are used for a wide range of proteins with highly variable properties in complex matrices. These methods usually work reasonably well for proteins under controlled conditions, but the results for non-standard and complex samples are often questionable. Here, we compare new and well-established methods, including traditional amino acid analysis (AAA), aromatic amino acid analysis (AAAA) based on the amino acids phenylalanine and tyrosine, reversed-phase liquid chromatography of intact proteins with UV absorbance measurements at 220 and 280 nm (LC-220, LC-280), and colorimetric assays like Coomassie Blue G-250 dye-binding assay (Bradford) and bicinchoninic acid (BCA) assay. We investigated different samples, including proteins with challenging properties, chemical modifications, mixtures, and complex matrices like air particulate matter and pollen extracts. All methods yielded accurate and precise results for the protein and matrix used for calibration. AAA, AAAA with fluorescence detection, and the LC-220 method yielded robust results even under more challenging conditions (variable analytes and matrices). These methods turned out to be well-suited for reliable determination of the protein content in a wide range of samples, such as air particulate matter and pollen.
KW - Air particulate matter
KW - Aromatic amino acid analysis
KW - Atmospheric aerosol
KW - Chemical protein modification
KW - Derivatization
KW - Nitration
KW - Nitrotyrosine
KW - LC-UV absorbance
KW - Pollen extract
KW - Protein quantification
KW - Protein test
KW - Kjeldahl
KW - Tyrosine
KW - Phenylalanine
KW - Hydrolysis
KW - Bradford
KW - BCA test
KW - 280 nm
KW - Air filter samples
KW - Fluorescence
KW - HPLC
KW - Chromatography
KW - Protein content
KW - 150th anniversary of BAM
KW - Topical collection: Analytical Methods and Applications in the Materials and Life Sciences
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545924
UR - https://pubmed.ncbi.nlm.nih.gov/35320366/
DO - https://doi.org/10.1007/s00216-022-03910-1
SP - 1
EP - 14
PB - Springer Nature Limited
CY - New York, Heidelberg
AN - OPUS4-54592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Biyikal, Mustafa
A1 - Gröninger, Delia
A1 - Weller, Michael G.
A1 - Martínez Mánez, R.
A1 - Rurack, Knut
ED - Climent Terol, Estela
T1 - Multiplexed Detection of Analytes on Single Test Strips with Antibody-Gated Indicator-Releasing Mesoporous Nanoparticles
N2 - Rapid testing methods for the use directly at apointof need are expected to unfold their true potential especiallywhen offering adequate capabilities for the simultaneousmeasurement of multiple analytes of interest. Considering theunique modularity,high sensitivity,and selectivity of antibody-gated indicator delivery (gAID) systems,amultiplexed assayfor three small-molecule explosives (TATP, TNT,PETN) wasthus developed, allowing to detect the analytes simultaneouslywith asingle test strip at lower ppb concentrations in the liquidphase in < 5min using afluorescence reader or asmartphonefor readout. While the TNT and PETN systems were newlydeveloped here,all the three systems also tolerated harshermatrices than buffered aqueous model solutions.Besidesasingle-track strip,the outstanding modularity of the hybridbiosensor materials in combination with strip-patterningtechnologies allowed us to obtain amultichannel strip inastraightforwardmanner,offering comparable analyticalperformance while allowing to be tailored even more to theusersneed.
KW - Multiplexing
KW - Explosives detection
KW - Gated materials
KW - Fluorescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518424
DO - https://doi.org/10.1002/anie.202009000
SN - 1433-7851
SN - 1521-3773
VL - 59
IS - 52
SP - 23862
EP - 23869
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-51842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Abbassi, Abdelouahad
A1 - Krenzer, Julius
A1 - Petrov, Eugene P.
A1 - Biesen, Lukas
A1 - Vasylyeva, Vera
A1 - Merzenich, Sarah
A1 - Resch-Genger, Ute
A1 - Müller, Thomas J. J.
T1 - Aroyl-S,N-ketene acetal-triarylamine bichromophores – intramolecular energy transfer and dual emission upon induced aggregation and encapsulation
N2 - Aroyl-S,N-ketene acetal-based bichromophores are synthesized by a catalytic aryl amination and their photophysics are studied in the solid state, in ethanol–water mixtures inducing aggregation, and after encapsulation in polystyrene nanoparticles. The dye substitution pattern controls aggregation-induced emission and intramolecular energy transfer efficiency, resulting in single-band or dual fluorescence and a strong increase in fluorescence quantum yield upon particle encapsulation.
KW - Fluorescence
KW - Dye
KW - Aggregation
KW - Photophysics
KW - Enhancement
KW - White light emission
KW - Energy transfer
KW - Quantum yield
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656700
DO - https://doi.org/10.1039/d5ra09361a
SN - 2046-2069
VL - 16
IS - 11
SP - 10255
EP - 10260
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pérez-Padilla, Víctor
A1 - Burnage, Samual C.
A1 - Wittwer, Philipp
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Detection of Perfluoroalkylic Acids From Water Using a Guanidine-Based Fluorescent Probe and Microfluidic Droplet Extraction
N2 - Perfluoroalkylic acids (PFAAs), a subclass of per- and polyfluoroalkyl substances (PFAS), are stable, widely used industrial compounds posing environmental concerns due to their persistence and toxicity. Regulatory actions and remediation strategies necessitate effective onsite analytical methods for PFAS management. We developed an optical sensing system using a fluorescent probe with a benzoxadiazole core and guanidine receptor in a droplet-based microfluidic assay to detect PFAAs in water samples with low detection limits. The PFAAs binding enhances the probe's fluorescence in organic media through protonation-mediated hydrogen bond-assisted ion pairing, exploiting two complementary supramolecular forces. Direct detection employs a liquid-liquid extraction protocol in the microfluidic device, achieving detection limits for PFOA and PFOS down to ≥0.5 µm, with a dynamic range up to 200 µm for sample volumes <100 µL. HCl/KCl buffering facilitates analyte desalting and phase transfer for quantitation from surface water. Additionally, we developed a method involving a thin polymer layer of the probe and a crosslinker on submicron silica particles for direct detection of PFAAs in water. Our approaches provide sensitive, direct recognition and indication of PFAAs, advancing the field beyond indirect sensing and offering improved background suppression, rapid assay times, and a modular design for targeting other PFAS subclasses.
KW - PFAS
KW - Fluorescence
KW - Microfluidics
KW - Droplet Extraction
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657330
DO - https://doi.org/10.1002/adsr.70145
VL - 5
IS - 3
SP - 1
EP - 13
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-65733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -